text: /*
  
   u8x8_d_ssd1306_2040x16.c
  
   Universal 8bit Graphics Library (https://github.com/olikraus/u8g2/)
  
   Copyright (c) 2016, olikraus@gmail.com
   All rights reserved.
  
   Redistribution and use in source and binary forms, with or without modification,
   are permitted provided that the following conditions are met:
  
   * Redistributions of source code must retain the above copyright notice, this list
   of conditions and the following disclaimer.
  
   * Redistributions in binary form must reproduce the above copyright notice, this
   list of conditions and the following disclaimer in the documentation and/or other
   materials provided with the distribution.
  
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
   CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
   */
  #include "u8x8.h"
  
  /* virtual device, issue 1291 */
  static const uint8_t u8x8_d_ssd1306_2040x16_init_seq[] =
  {
  
  U8X8_START_TRANSFER(), /* enable chip, delay is part of the transfer start */
  
      U8X8_C(0x0ae), /* display off */
      U8X8_CA(0x0d5, 0x080), /* clock divide ratio (0x00=1) and oscillator frequency (0x8) */
      U8X8_CA(0x0a8, 0x03f), /* multiplex ratio, 0.71 OLED: changed from 0x2f to 0x3f */
      U8X8_CA(0x0d3, 0x000), /* display offset, 0.71 OLED  */
      U8X8_C(0x040), /* set display start line to 0, 0.71 OLED */
      U8X8_CA(0x08d, 0x014), /* [2] charge pump setting (p62): 0x014 enable, 0x010 disable, 0.71 OLED  0x14*/
  
      /// according to the datasheet, 0x00 is NOT page addressing mode, but horizontal addressing mode;
      /// so it looks like u8g2 expects horizontal addressing (and the inline comment is wrong) while the Winstar example
      /// actually uses page addressing (which is the reset default)
      U8X8_CA(0x020, 0x000), /* horizontal addressing mode */
  
      U8X8_C(0x0a1), /* segment remap a0/a1, 0.71 OLED  */
      U8X8_C(0x0c8), /* c0: scan dir normal, c8: reverse, 0.71 OLED  */
      // Flipmode
      // U8X8_C(0x0a0),       /* segment remap a0/a1*/
      // U8X8_C(0x0c0),       /* c0: scan dir normal, c8: reverse */
  
      U8X8_CA(0x0da, 0x012), /* com pin HW config, sequential com pin config (bit 4), disable left/right remap (bit 5), 0.71 OLED */
      U8X8_CA(0x081, 0x07f), /* [2] set contrast control, 0.71 OLED datasheet: 0x7f */
      U8X8_CA(0x0d9, 0x022), /* [2] pre-charge period 0x022/f1, 0.71 OLED datasheet: 0x22 */
      U8X8_CA(0x0db, 0x040), /* vcomh deselect level, 0.71 OLED datasheet: 0x40 */
  
      // U8X8_C(0x02e),        /* Deactivate scroll */
      U8X8_C(0x0a4), /* output ram to display */
      U8X8_C(0x0a6), /* none inverted normal display mode */
  
      U8X8_END_TRANSFER(), /* disable chip */
      U8X8_END() /* end of sequence */
  };
  
  static const uint8_t u8x8_d_ssd1306_2040x16_powersave0_seq[] =
  {
  U8X8_START_TRANSFER(), /* enable chip, delay is part of the transfer start */
  U8X8_C(0x0af), /* display on */
  U8X8_END_TRANSFER(), /* disable chip */
  U8X8_END() /* end of sequence */
  };
  
  static const uint8_t u8x8_d_ssd1306_2040x16_powersave1_seq[] =
  {
  U8X8_START_TRANSFER(), /* enable chip, delay is part of the transfer start */
  U8X8_C(0x0ae), /* display off */
  U8X8_END_TRANSFER(), /* disable chip */
  U8X8_END() /* end of sequence */
  };
  
  static const uint8_t u8x8_d_ssd1306_2040x16_flip0_seq[] =
  {
  U8X8_START_TRANSFER(), /* enable chip, delay is part of the transfer start */
  U8X8_C(0x0a1), /* segment remap a0/a1*/
  U8X8_C(0x0c8), /* c0: scan dir normal, c8: reverse */
  U8X8_END_TRANSFER(), /* disable chip */
  U8X8_END() /* end of sequence */
  };
  
  static const uint8_t u8x8_d_ssd1306_2040x16_flip1_seq[] =
  {
  U8X8_START_TRANSFER(), /* enable chip, delay is part of the transfer start */
  U8X8_C(0x0a0), /* segment remap a0/a1*/
  U8X8_C(0x0c0), /* c0: scan dir normal, c8: reverse */
  U8X8_END_TRANSFER(), /* disable chip */
  U8X8_END() /* end of sequence */
  };
  
  static uint8_t u8x8_d_ssd1306_2040x16_generic(u8x8_t *u8x8, uint8_t msg,
      uint8_t arg_int, void *arg_ptr)
  {
    uint8_t x, c;
    uint8_t *ptr;
    switch (msg)
    {
      /* handled by the calling function
       case U8X8_MSG_DISPLAY_SETUP_MEMORY:
       u8x8_d_helper_display_setup_memory(u8x8, &u8x8_ssd1306_2040x16_display_info);
       break;
       case U8X8_MSG_DISPLAY_INIT:
       u8x8_d_helper_display_init(u8x8);
       u8x8_cad_SendSequence(u8x8, u8x8_d_ssd1306_2040x16_init_seq);
       break;
       */
      case U8X8_MSG_DISPLAY_SET_POWER_SAVE:
        if (arg_int == 0)
          u8x8_cad_SendSequence(u8x8, u8x8_d_ssd1306_2040x16_powersave0_seq);
        else
          u8x8_cad_SendSequence(u8x8, u8x8_d_ssd1306_2040x16_powersave1_seq);
        break;
      case U8X8_MSG_DISPLAY_SET_FLIP_MODE:
        if (arg_int == 0)
        {
          u8x8_cad_SendSequence(u8x8, u8x8_d_ssd1306_2040x16_flip0_seq);
          u8x8->x_offset = u8x8->display_info->default_x_offset;
        }
        else
        {
          u8x8_cad_SendSequence(u8x8, u8x8_d_ssd1306_2040x16_flip1_seq);
          u8x8->x_offset = u8x8->display_info->flipmode_x_offset;
        }
        break;
  #ifdef U8X8_WITH_SET_CONTRAST
      case U8X8_MSG_DISPLAY_SET_CONTRAST:
        u8x8_cad_StartTransfer(u8x8);
        u8x8_cad_SendCmd(u8x8, 0x081);
        u8x8_cad_SendArg(u8x8, arg_int); /* ssd1306 has range from 0 to 255 */
        u8x8_cad_EndTransfer(u8x8);
        break;
  #endif
      case U8X8_MSG_DISPLAY_DRAW_TILE:
        u8x8_cad_StartTransfer(u8x8);
        x = ((u8x8_tile_t *) arg_ptr)->x_pos;
        x *= 8;
        x += u8x8->x_offset;
        u8x8_cad_SendCmd(u8x8, 0x010 | (x >> 4));
        u8x8_cad_SendCmd(u8x8, 0x000 | ((x & 15)));
        u8x8_cad_SendCmd(u8x8, 0x0b0 | (((u8x8_tile_t *) arg_ptr)->y_pos));
  
        do
        {
          c = ((u8x8_tile_t *) arg_ptr)->cnt;
          ptr = ((u8x8_tile_t *) arg_ptr)->tile_ptr;
          u8x8_cad_SendData(u8x8, c * 8, ptr); /* note: SendData can not handle more than 255 bytes */
          arg_int--;
        } while (arg_int > 0);
  
        u8x8_cad_EndTransfer(u8x8);
        break;
      default:
        return 0;
    }
    return 1;
  }
  
  static const u8x8_display_info_t u8x8_ssd1306_2040x16_display_info =
  {
  /* chip_enable_level = */0,
  /* chip_disable_level = */1,
  
  /* post_chip_enable_wait_ns = */20,
  /* pre_chip_disable_wait_ns = */10,
  /* reset_pulse_width_ms = */100, /* SSD1306: 3 us */
  /* post_reset_wait_ms = */100, /* far east OLEDs need much longer setup time */
  /* sda_setup_time_ns = */50, /* SSD1306: 15ns, but cycle time is 100ns, so use 100/2 */
  /* sck_pulse_width_ns = */50, /* SSD1306: 20ns, but cycle time is 100ns, so use 100/2, AVR: below 70: 8 MHz, >= 70 --> 4MHz clock */
  /* sck_clock_hz = */8000000UL, /* since Arduino 1.6.0, the SPI bus speed in Hz. Should be  1000000000/sck_pulse_width_ns, increased to 8MHz (issue 215) */
  /* spi_mode = */0, /* active high, rising edge */
  /* i2c_bus_clock_100kHz = */4,
  /* data_setup_time_ns = */40,
  /* write_pulse_width_ns = */150, /* SSD1306: cycle time is 300ns, so use 300/2 = 150 */
  /* tile_width = */255,
  /* tile_height = */2,
  /* default_x_offset = */0,
  /* flipmode_x_offset = */0,
  /* pixel_width = */2040,
  /* pixel_height = */16 };
  
  uint8_t u8x8_d_ssd1306_2040x16(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
  {
    if (msg == U8X8_MSG_DISPLAY_SETUP_MEMORY)
    {
      u8x8_d_helper_display_setup_memory(u8x8, &u8x8_ssd1306_2040x16_display_info);
      return 1;
    }
    else if (msg == U8X8_MSG_DISPLAY_INIT)
    {
      u8x8_d_helper_display_init(u8x8);
      u8x8_cad_SendSequence(u8x8, u8x8_d_ssd1306_2040x16_init_seq);
      return 1;
    }
    return u8x8_d_ssd1306_2040x16_generic(u8x8, msg, arg_int, arg_ptr);
  }
  
  